[Mike C]

I think the 15" wheel would fit on the 6 lug sf 14, but I can't guarantee that. I'm almost positive it would fit with a disc conversion on the back. The Z-71 may have come with 15" wheels in the beginning before going to 16's, but I don't know the years.

Your 15" would probably work with a disc conversion in the rear but would need to verify with kit manufacturer.

My 12 bolt has been broken at least 7 times. 35" tires, granny gear 4 speed, high miles, wheel hop, warped differential carrier, weird backfire while turning it off and letting the clutch out. (That was the first one on my dad in something like 1980). If you aren't planning on driving hard or 100's of thousand miles (my Jimmy has 350,000 miles on it) I wouldn't worry about it.

And when you do break it, I would seriously consider 8 lug axles but that does mean new wheels and tires. Eventually tires have to be replaced (and if you are worrying about broken axles on a street truck, you should REALLY be worried about older tires coming apart which is way more likely.)